Effect of laser spot overlap ratio on surface characteristics and adhesive bonding strength of an Al alloy processed by nanosecond pulsed laser

Wan, Hailang; Min, Junying; Lin, Jianping; Carlson, Blair E.; Maddela, Surender; Sun, Chengcheng

doi:10.1016/j.jmapro.2020.12.055

Cited by 40 publications

(16 citation statements)

References 21 publications

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“…However, a few microvoids were found in the adhesive layer of samples fabricated with spindle substrates having a surface roughness over 1.7 μm. This is particularly evident for the case of a surface roughness of 12.8 μm, and attributed to some trapped air bubbles diffusing into adhesive layer …”

Section: Resultsmentioning

confidence: 93%

“…The overlap ratio between laser spots was calculated as dividing the width of the overlapped area by the diameter of the laser spot in accordance with a previously published paper. 27 The detailed processing parameters of laser ablation are listed in Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…It is testified that the laser ablation with a spacing of 55 μm between laser spots (corresponding to an overlap ratio of 21% as shown in Figure S1a) produced bioinspired spindle microstructures on aluminum material, and the dimple microstructures were fabricated to be taken as a reference by laser ablation with a spacing of 85 μm between laser spots (corresponding to an overlap ratio of −21% as shown in Figure S1b). The overlap ratio between laser spots was calculated as dividing the width of the overlapped area by the diameter of the laser spot in accordance with a previously published paper . The detailed processing parameters of laser ablation are listed in Table .…”

Section: Methodsmentioning

confidence: 99%

“…This is particularly evident for the case of a surface roughness of 12.8 μm, and attributed to some trapped air bubbles diffusing into adhesive layer. 27 The complete wetting of adhesive on dimple microstructures was also observed for dimple substrates having low levels of surface roughness (i.e., 2.1 and 5.3 μm) as seen in Figure 7k− n. However, the nonwetting phenomenon of adhesive on dimple microstructures initially occurred for dimple substrates having a surface roughness of 8.4 μm, refer to Figure 7o, p. The further increased surface roughness continuously deteriorated the interfacial wettability of adhesive on dimple microstructures, and more air bubbles were trapped in dimple microstructures to subsequently form more micropore defects As a result, the surface microstructure plays an importance role in the interfacial wetting of adhesive on substrate surface, and the spindle microstructures bioinspired by directional water collection biosystems apparently possess better interfacial wettability to used epoxy adhesive (Dow Betamate 1486) than common dimple microstructures, which shows no obvious degradation with the increasing of surface roughness.…”

Section: Observations Of Interfacialmentioning

confidence: 99%

See 3 more Smart Citations

Spindle-Shaped Surface Microstructure Inspired by Directional Water Collection Biosystems to Enhance Interfacial Wetting and Bonding Strength

Wan

Min

Carlson

et al. 2021

ACS Appl. Mater. Interfaces

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Unique spindle microstructures with an apex angle of ∼20° bring the ability of directional water collection to various biosystems (i.e., spider silk and cactus stem). This has great potential to solve the insufficient interfacial wetting for mechanical interlocking formation between polymers and substrates. In this study, the bioinspired spindle microstructures were easily fabricated through the deposition of molten materials by a nanosecond laser with an overlap ratio of 21% between laser spots and achieved superior interfacial wetting for commercial epoxy adhesive on aluminum substrates. Detailed analyses show that there are four mechanisms responsible for the superior interfacial wettability of bioinspired spindle microstructures: the Laplace pressure difference, newly formed aluminum oxide, the capillary effect, and no extra pressure from a trapped atmosphere. Consequently, the bioinspired spindle surface microstructures achieve a maximum improvement of ∼16 and ∼39% in interfacial bonding strength before and after water soak exposure compared to the as-received condition. Moreover, the stable interfacial wettability of bioinspired spindle microstructures ensures that the improved joint strength varied little with an increase in surface roughness from ∼1.7 to ∼12.8 μm. However, the interfacial wettability of common dimple microstructures deteriorated with an increase in surface roughness, which is indicated by the decreasing rule in the quadratic polynomial function of the interfacial bonding strength as the surface roughness increases from ∼2.1 to ∼18.2 μm.

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Section: Resultsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Observations Of Interfacialmentioning

confidence: 99%

See 2 more Smart Citations

Spindle-Shaped Surface Microstructure Inspired by Directional Water Collection Biosystems to Enhance Interfacial Wetting and Bonding Strength

Wan

Min

Carlson

et al. 2021

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…One noteworthy aspect is that all authors agree that the use of lasers requires a thorough knowledge and experience of the process and precise optimization of the treatment parameters according to the material to be treated. Once the correct wavelength has been chosen so as not to damage the substrate, there is a huge number of laser parameters to consider in order to achieve highly controlled and repeatable surface properties: power, pulse frequency, spot size, focal distance, scanning velocity, and spot pattern, to name a few [ 18 , 19 , 20 , 21 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

A Response Surface Methodology Approach to Improve Adhesive Bonding of Pulsed Laser Treated CFRP Composites

et al. 2022

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In this work, a response surface-designed experiment approach was used to determine the optimal settings of laser treatment as a method of surface preparation for CFRP prior to bonding. A nanosecond pulsed Ytterbium-doped-fiber laser source was used in combination with a scanning system. A Face-centered Central Composite Design was used to model the tensile shear strength (TSS) of adhesive bonded joints and investigate the effects of varying three parameters, namely, power, pitch, and lateral overlap. The analysis was carried out considering different focal distances. For each set of joints, shear strength values were modeled using Response Surface Methodology (RSM) to identify the set-up parameters that gave the best performance, determining any equivalent conditions from a statistical point of view. The regression models also allow the prediction of the behavior of the joints for not experimentally tested parameter settings, within the operating domain of investigation. This aspect is particularly important in consideration of the process optimization of the manufacturing cycle since it allows the maximization of joint efficiency by limiting the energy consumption for treatment.

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Laser Surface Modification on Titanium Bipolar Plate of Hydrogen Fuel Cell to Enhance Bonding Performance

Min,

Lv,

Wan

et al. 2023

Lecture Notes in Mechanical Engineering

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Effect of laser spot overlap ratio on surface characteristics and adhesive bonding strength of an Al alloy processed by nanosecond pulsed laser

Cited by 40 publications

References 21 publications

Spindle-Shaped Surface Microstructure Inspired by Directional Water Collection Biosystems to Enhance Interfacial Wetting and Bonding Strength

Spindle-Shaped Surface Microstructure Inspired by Directional Water Collection Biosystems to Enhance Interfacial Wetting and Bonding Strength

A Response Surface Methodology Approach to Improve Adhesive Bonding of Pulsed Laser Treated CFRP Composites

Laser Surface Modification on Titanium Bipolar Plate of Hydrogen Fuel Cell to Enhance Bonding Performance

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